Fix OverlappingFileLockException. (#1536)

* Dropping guava and appcompat dependency from FIS SDK.

* Fix OverlappingFileLockException.

Access the data shared by multiple threads only after acquiring cross-process and multi-thread safe locks.

Author: ankitaj224

firebase-installations/gradle.properties

@@ -1,2 +1,2 @@
-version=16.2.2
-latestReleasedVersion=16.2.1
+version=16.3.0
+latestReleasedVersion=16.2.2

firebase-installations/src/main/java/com/google/firebase/installations/FirebaseInstallations.java

@@ -351,7 +351,7 @@ private void doNetworkCall(boolean forceRefresh) {
     }
 
     // Store the prefs to persist the result of the previous step.
-    persistedInstallation.insertOrUpdatePersistedInstallationEntry(prefs);
+    insertOrUpdatePrefs(prefs);
 
     // Let the caller know about the result.
     if (prefs.isErrored()) {
@@ -365,6 +365,29 @@ private void doNetworkCall(boolean forceRefresh) {
     }
   }
 
+  /**
+   * Inserting or Updating the prefs. This operation is made cross-process and cross-thread safe by
+   * wrapping all the processing first in a java synchronization block and wrapping that in a
+   * cross-process lock created using FileLocks.
+   */
+  private void insertOrUpdatePrefs(PersistedInstallationEntry prefs) {
+    synchronized (lockGenerateFid) {
+      CrossProcessLock lock =
+          CrossProcessLock.acquire(firebaseApp.getApplicationContext(), LOCKFILE_NAME_GENERATE_FID);
+      try {
+        // Store the prefs to persist the result of the previous step.
+        persistedInstallation.insertOrUpdatePersistedInstallationEntry(prefs);
+      } finally {
+        // It is possible that the lock acquisition failed, resulting in lock being null.
+        // We handle this case by going on with our business even if the acquisition failed
+        // but we need to be sure to only release if we got a lock.
+        if (lock != null) {
+          lock.releaseAndClose();
+        }
+      }
+    }
+  }
+
   /**
    * Loads the prefs, generating a new ID if necessary. This operation is made cross-process and
    * cross-thread safe by wrapping all the processing first in a java synchronization block and
@@ -513,7 +536,7 @@ private Void deleteFirebaseInstallationId() throws FirebaseInstallationsExceptio
       }
     }
 
-    persistedInstallation.insertOrUpdatePersistedInstallationEntry(entry.withNoGeneratedFid());
+    insertOrUpdatePrefs(entry.withNoGeneratedFid());
     return null;
   }
 }